The overall goal of this project is to develop a computerized self- management program for modifying exercise habits. The computer-assisted exercise program (CASE) will incorporate a hand-held computer for structuring the intervention and a written program guide that provides educational and product use information. The product will be unique because it will incorporate the critical features of successful clinic- based programs for lifestyle intervention and package them in a hand- held computer. The computerized delivery format will offer many unique features, e.g., interactive prompts, instantaneous feedback, and simplified self-monitoring that may result in greater ease of use and effectiveness than traditional manual-based self-management programs. Furthermore, a computer-assisted program may provide the structure necessary to enhance long-term maintenance where many other approaches have been unsuccessful. The entire development project, incorporating both Phase I and Phase II, with follow a structured "proof of concept" approach that involves several iterative cycles of prototype development, testing, and refinement. This Phase I project will include development of a first generation prototype system and a 14-week feasibility study, (i.e., a two-week baseline period followed by a 12-week intervention period) with 30 healthy adult volunteers who will use the product. Criteria for feasibility will be statistically significant increases in weekly caloric expenditure from exercise and changes in one or more physical parameters including weight, blood pressure, percentage body fat, and resting pulse. During Phase II a second generation product will be developed and a randomized outcome trial will be conducted to compare the CASE program with traditional self-help materials. PROPOSED COMMERCIAL APPLICATION: Despite the widely publicized link between sedentary lifestyle and a variety of adverse health outcomes. 60% of adult Americans are not regularly physically active and only about 15% meet minimal exercise targets set forth in federal guidelines. A simple to use self-help intervention for structuring and guiding exercise behavior could provide an effective means of enhancing exercise activity among a large number of sedentary adults.